diff --git a/.gitea/scripts/sop-tier-check.sh b/.gitea/scripts/sop-tier-check.sh
index afd13e48b..d1bd2c235 100755
--- a/.gitea/scripts/sop-tier-check.sh
+++ b/.gitea/scripts/sop-tier-check.sh
@@ -114,6 +114,19 @@ if [ -z "$WHOAMI" ]; then
 fi
 echo "::notice::token resolves to user: $WHOAMI"
 
+# 0.5 Read PR head SHA so we can reject stale approvals after head moves
+# (internal#816). Reviews carry the commit_id they were submitted against.
+HEAD_SHA=$(curl -sS -H "$AUTH" "${API}/repos/${OWNER}/${NAME}/pulls/${PR_NUMBER}" | jq -r '.head.sha // ""') || true
+if [ -z "$HEAD_SHA" ]; then
+  echo "::error::Failed to fetch PR head SHA — token may be invalid."
+  if [ "${SOP_FAIL_OPEN:-}" = "1" ]; then
+    echo "::warning::SOP_FAIL_OPEN=1 — exiting 0 so CI does not block."
+    exit 0
+  fi
+  exit 1
+fi
+debug "pr-head-sha=$HEAD_SHA"
+
 # 1. Read tier label. || true ensures set -euo pipefail does not abort the
 # script if curl or jq fails (e.g. 401 from empty token).
 LABELS=$(curl -sS -H "$AUTH" "${API}/repos/${OWNER}/${NAME}/issues/${PR_NUMBER}/labels" | jq -r '.[].name') || true
@@ -265,7 +278,7 @@ if [ $_REVIEWS_EXIT -ne 0 ] || [ -z "$REVIEWS" ]; then
   fi
   exit 1
 fi
-APPROVERS=$(echo "$REVIEWS" | jq -r '[.[] | select(.state=="APPROVED") | .user.login] | unique | .[]') || true
+APPROVERS=$(echo "$REVIEWS" | jq -r --arg head_sha "$HEAD_SHA" '[.[] | select(.state=="APPROVED" and .commit_id == $head_sha) | .user.login] | unique | .[]') || true
 if [ -z "$APPROVERS" ]; then
   echo "::error::No approving reviews on this PR. Set SOP_DEBUG=1 and re-run for diagnostics."
   exit 1
diff --git a/.gitea/scripts/tests/test_sop_tier_check_stale_reviews.sh b/.gitea/scripts/tests/test_sop_tier_check_stale_reviews.sh
new file mode 100755
index 000000000..a5afe8663
--- /dev/null
+++ b/.gitea/scripts/tests/test_sop_tier_check_stale_reviews.sh
@@ -0,0 +1,66 @@
+#!/usr/bin/env bash
+# Regression test for internal#816 — sop-tier-check must ignore APPROVED
+# reviews that were submitted against an old PR head SHA.
+#
+# Bug: the script collected approvers with
+#   jq '[.[] | select(.state=="APPROVED") | .user.login]'
+# without filtering on .commit_id == HEAD_SHA. After a PR head moved,
+# stale approvals looked valid to the tier gate.
+#
+# Fix: the jq filter now includes
+#   select(.state=="APPROVED" and .commit_id == $head_sha)
+# where $head_sha is the current PR head fetched from the API.
+
+set -euo pipefail
+
+# jq may not be on PATH in all environments (e.g. dev containers).
+PATH="/tmp/bin:$PATH"
+command -v jq >/dev/null 2>&1 || { echo "::error::jq required but not found"; exit 1; }
+
+PASS=0
+FAIL=0
+
+assert_eq() {
+  local label="$1"
+  local expected="$2"
+  local got="$3"
+  if [ "$expected" = "$got" ]; then
+    echo "  PASS  $label"
+    PASS=$((PASS + 1))
+  else
+    echo "  FAIL  $label"
+    echo "        expected: <$expected>"
+    echo "        got:      <$got>"
+    FAIL=$((FAIL + 1))
+  fi
+}
+
+# Sample reviews matching the shape from Gitea API
+REVIEWS_JSON='[
+  {"state":"APPROVED","commit_id":"abc123","user":{"login":"bob"}},
+  {"state":"APPROVED","commit_id":"old456","user":{"login":"alice"}},
+  {"state":"COMMENT","commit_id":"abc123","user":{"login":"carol"}},
+  {"state":"APPROVED","commit_id":"abc123","user":{"login":"dave"}},
+  {"state":"REQUEST_CHANGES","commit_id":"abc123","user":{"login":"eve"}}
+]'
+
+echo "test: jq filter keeps only APPROVED on current head"
+GOT=$(echo "$REVIEWS_JSON" | jq -r --arg head_sha "abc123" \
+  '[.[] | select(.state=="APPROVED" and .commit_id == $head_sha) | .user.login] | unique | .[]')
+assert_eq "current-head approvers" "bob dave" "$(echo "$GOT" | tr '\n' ' ' | sed 's/ $//')"
+
+echo "test: jq filter with all-stale reviews yields empty"
+GOT=$(echo "$REVIEWS_JSON" | jq -r --arg head_sha "new789" \
+  '[.[] | select(.state=="APPROVED" and .commit_id == $head_sha) | .user.login] | unique | .[]')
+assert_eq "all-stale yields empty" "" "$GOT"
+
+echo "test: jq filter handles null commit_id gracefully"
+NULL_JSON='[{"state":"APPROVED","commit_id":null,"user":{"login":"mallory"}}]'
+GOT=$(echo "$NULL_JSON" | jq -r --arg head_sha "abc123" \
+  '[.[] | select(.state=="APPROVED" and .commit_id == $head_sha) | .user.login] | unique | .[]')
+assert_eq "null commit_id excluded" "" "$GOT"
+
+echo
+echo "------"
+echo "PASS=$PASS FAIL=$FAIL"
+[ "$FAIL" -eq 0 ]